Signs and symptoms of SCID

Babies with SCID may seem well at birth and for the first few weeks of life. This is because they are partly protected by antibodies passed from mother to baby across the placenta during the last few months of pregnancy.

The first signs of SCID usually occur within the first three to six months. The baby is likely to suffer infections more frequently than other infants, and ordinary problems, such as coughs and colds, will seem more severe and last longer than
would be expected, requiring repeated and prolonged courses of treatment. Thrush (an infection caused by the yeast candida) in the mouth and/or nappy area may be severe and persistent, not clearing with usual treatment. The infant may feed poorly, have chronic diarrhoea and fail to gain weight normally, even if no definite infection is found. Skin rashes are common, and may be caused by thrush, or sometimes by a reaction in the skin caused by maternal blood cells which have crossed the placenta at birth.

Germs in the environment that don’t cause disease in healthy individuals can cause serious and life-threatening illness in a child with SCID. In particular, the
fungi Pneumocystis jirovecii (PJP) and Aspergillus, and the virus cytomegalovirus
(CMV), can cause severe infection (most frequently pneumonia). The parasite
Cryptosporidium (sometimes found in drinking water) can cause severe diarrhoea and sometimes liver disease in children with SCID.

Common childhood infections, such as chickenpox (varicella) and cold sore virus
(herpes simplex), can also be dangerous for a baby with SCID and may be life- threatening.

Reviewed April 2017